EPICAN, A PROTEOGLYCAN FORM OF CD44 ON KERATINOCYTES

表皮角质形成细胞表面有丰富的蛋白多糖，但 它们的功能尚不清楚。细胞-细胞黏附相互作用起到了 在正常组织和病理性组织中起中心作用。伊壁鸠鲁，一个 新发现的硫酸乙酰肝素形式的CD44，已在 角质形成细胞和初步数据表明外膜蛋白可以发挥作用 作为角质形成细胞上的黏附分子。 这项建议的目的是： I.剖析表皮细胞介导的角质形成细胞的分子基础-- 角质形成细胞黏附。我们建议a)确定在粘连中的作用 透明质酸、共价连接的硫酸乙酰肝素和N- 连接糖；b)鉴定外膜核心蛋白上的结合部位 或者通过创建epican的缺失突变体来阻止结合 转染体到角质形成细胞或使用合成肽面板 和/或区域特异性的单抗以阻断细胞间的黏附； 二、确定表现主义表达的功能后果 角质形成细胞。我们建议测试epcan在a)细胞中的作用。 细胞-基质黏附b)生长调节和c)细胞和组织 在自发性角质形成细胞系中抑制epcan的形态 表达低水平的EPICAN。 三、确定《教规》表达对 黑素细胞通过检查a)epcan是在什么条件下 在黑素细胞上表达；b)外膜蛋白表达对生长的影响， 黑素细胞或黑色素瘤细胞的形态和黏附特性。

Proteoglycans are abundant on the surface of epidermal keratinocytes, but their function is unknown. Cell-cell adhesive interactions play a central role in normal and pathologic tissue organization. Epican, a newly discovered heparan sulfate form of CD44, has been found on keratinocytes and preliminary data indicate that epican could function as an adhesion molecule on keratinocytes. The aims of this proposal are to: I. Dissect the molecular basis for epican-mediated keratinocyte- keratinocyte adhesion. We propose to a) determine the role in adhesion of hyaluronic acid, the covalently-linked heparan sulfate and the N- linked sugars; b) identify the binding site on the epican core protein either by creating deletion mutants of epican that prevent binding of transfectants to keratinocytes or by using panels of synthetic peptides and/or domain-specific monoclonal antibodies to block cell-cell adhesion; II. Determine the functional consequences of epican expression on keratinocytes. We propose to test the role of epican in a) cell-cell and cell-matrix adhesion b) growth regulation and c) cell and tissue morphology by overpressing epican in spontaneous keratinocyte lines that express low levels of epican. III. Determine that functional consequences of epican expression on melanocytes by examining a) the conditions under which epican is expressed on melanocytes; b) the effects of epican expression on growth, morphology and adhesive characteristics of melanocytes or melanoma cells.